Terminal apparatus, method, and integrated circuit

ABSTRACT

A terminal apparatus for communicating with one or more base station apparatuses, the terminal apparatus including: a receiver configured to receive an RRC reconfiguration message including a DRB configuration from the one or more base station apparatuses, the DRB configuration including a DRB identity and an EPS bearer identity; and a processing unit configured to associate a DRB established with the EPS identity in a case that the DRB identity is not part of a current configuration of the terminal apparatus, and the DRB was configured for the EPS bearer identity.

TECHNICAL FIELD

The present invention relates to a terminal apparatus, a method, and anintegrated circuit. This application claims priority to JP 2017-253553filed on Dec. 28, 2017, the contents of which are incorporated herein byreference.

BACKGROUND ART

A radio access scheme and a radio network for cellular mobilecommunications (which will hereinafter be referred to as “Long TermEvolution (LTE (trade name))” or “Evolved Universal Terrestrial RadioAccess (EUTRA)”) and a core network (which will be referred to as“Evolved Packet Core (EPC)”) have been studied by the 3rd GenerationPartnership Project (3GPP).

As a radio access scheme and a radio network technology for a 5thgeneration cellular system, technical studies and standardization ofLTE-Advanced Pro, which is an enhanced technology of LTE, and New Radiotechnology (NR), which is a new radio access technology, have beenconducted by the 3GPP (NPL 1). 5 Generation Core Network (5GC), which isa core network for a 5th generation cellular system, has also beenstudied (NPL 2).

CITATION LIST Non Patent Literature

NPL 1: 3GPP RP-170855, “Work Item on New Radio (NR) Access Technology”

NPL 2: 3GPP TS 23.501, “System Architecture for the 5G System; Stage 2”

NPL 3: 3GPP TS 36.300, “Evolved Universal Terrestrial Radio Access(E-UTRA) and Evolved Universal Terrestrial Radio Access Network(E-UTRAN); Overall description; Stage 2”

NPL 4: 3GPP TS 36.331, “Evolved Universal Terrestrial Radio Access(E-UTRA); Radio Resource Control (RRC); Protocol specifications”

NPL 5: 3GPP TS 36.323, “Evolved Universal Terrestrial Radio Access(E-UTRA); Packet Data Convergence Protocol (PDCP) specification”

NPL 6: 3GPP TS 36.322, “Evolved Universal Terrestrial Radio Access(E-UTRA); Radio Link Control (RLC) protocol specification”

NPL 7: 3GPP TS 36.321, “Evolved Universal Terrestrial Radio Access(E-UTRA); Medium Access Control (MAC) protocol specification”

NPL 8: 3GPP TS 37.340, “Evolved Universal Terrestrial Radio Access(E-UTRA) and NR; Multi-Connectivity; Stage 2”

NPL 9: 3GPP TS 38.300, “NR; NR and NG-RAN Overall description; Stage 2”

NPL 10: 3GPP TS 38.331, “NR; Radio Resource Control (RRC); Protocolspecifications”

NPL 11: 3GPP TS 38.323, “NR; Packet Data Convergence Protocol (PDCP)specification”

NPL 12: 3GPP TS 38.322, “NR; Radio Link Control (RLC) protocolspecification”

NPL 13: 3GPP TS 38.321, “NR; Medium Access Control (MAC) protocolspecification”

NPL 14: 3GPP TS 23.401v04.3.0, “General Packet Radio Service (GPRS)enhancements for Evolved Universal Terrestrial Radio Access Network(E-UTRAN) access”

NPL 15: 3GPP TS 23.502, “Procedure for 5G System; Stage 2”

NPL 16: 3GPP TS 37.324, “NR; Service Data Adaptation Protocol (SDAP)specification”

SUMMARY OF INVENTION Technical Problem

As one of the technical studies of NR, a scheme called Multi-RAT DualConnectivity (MR-DC) is being studied, which allows cells of RadioAccess Technologies (RATs) of both E-UTRA and NR to be made into cellgroups for each RAT and to be allocated to UE such that a terminalapparatus communicates with one or more base station apparatuses (NPL8).

However, since the formats and functions of the communication protocolsused in E-UTRA and NR differ, there is a problem in that protocolprocessing becomes complex compared to Dual Connectivity in conventionalLTE using only E-UTRA as the RAT, and thus a base station apparatus anda terminal apparatus are not able to efficiently communicate with eachother.

In view of the circumstances described above, an object of an aspect ofthe present invention is to provide a terminal apparatus capable ofefficiently communicating with a base station apparatus, a method usedfor the terminal apparatus, and an integrated circuit mounted on theterminal apparatus.

Solution to Problem

In order to accomplish the object described above, an aspect of thepresent invention is contrived to provide the following means.Specifically, an aspect of the present invention is a terminal apparatusfor communicating with one or more base station apparatuses, theterminal apparatus including: a receiver configured to receive an RRCreconfiguration message including a DRB configuration from the one ormore base station apparatuses, the DRB configuration including a DRBidentity and an EPS bearer identity; and a processing unit configured toassociate a DRB established with the EPS identity in a case that the DRBidentity is not part of a current configuration of the terminalapparatus, and the DRB was configured for the EPS bearer identity.

An aspect of the present invention is a communication method for aterminal apparatus for communicating with one or more base stationapparatuses, the communication method including the steps of: receivingan RRC reconfiguration message including a DRB configuration from theone or more base station apparatuses, the DRB configuration including aDRB identity and an EPS bearer identity, and associating a DRBestablished with the EPS identity in a case that the DRB identity is notpart of a current configuration of the terminal apparatus, and the DRBwas configured for the EPS bearer identity.

An aspect of the present invention is a base station apparatus forcommunicating with a terminal apparatus, the base station apparatusincluding: a transmitter configured to transmit an RRC reconfigurationmessage including a DRB configuration to the terminal apparatus, the DRBconfiguration including a DRB identity and an EPS bearer identity; and aprocessing unit configured to cause the terminal apparatus to performprocessing to associate a DRB established with the EPS identity in acase that the DRB identity is not part of a current configuration of theterminal apparatus, and the DRB was configured for the EPS beareridentity.

An aspect of the present invention is a communication method for a basestation apparatus for communicating with a terminal apparatus, thecommunication method including the steps of: transmitting an RRCreconfiguration message including a DRB configuration to the terminalapparatus, the DRB configuration including a DRB identity and an EPSbearer identity; and causing the terminal apparatus to performprocessing to associate a DRB established with the EPS identity in acase that the DRB identity is not part of a current configuration of theterminal apparatus, and the DRB was configured for the EPS beareridentity.

These comprehensive or specific aspects may be implemented in a system,an apparatus, a method, an integrated circuit, a computer program, or arecording medium, or may be implemented in any combination of systems,apparatuses, methods, integrated circuits, computer programs, andrecording media.

Advantageous Effects of Invention

According to an aspect of the present invention, the terminal apparatuscan lower complexity of protocol processing and communicate efficiently.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a communication system according toeach embodiment of the present invention.

FIG. 2 is a diagram of protocol stacks of UP and CP of a terminalapparatus and a base station apparatus in E-UTRA according to eachembodiment of the present invention.

FIG. 3 is a diagram of protocol stacks of UP and CP of a terminalapparatus and a base station apparatus in NR according to eachembodiment of the present invention.

FIG. 4 is a diagram illustrating an example of a flow of an RRCconnection reconfiguration procedure according to each embodiment of thepresent invention.

FIG. 5 is a block diagram illustrating a configuration of a terminalapparatus according to each embodiment of the present invention.

FIG. 6 is a diagram illustrating an example of information related to aDRB configuration and Abstract Syntax Notation One (ASN.1) descriptionof the information according to each embodiment of the presentinvention.

FIG. 7 is an example of a processing method according to Embodiment 1 ofthe present invention.

FIG. 8 is another example of a processing method according to Embodiment1 of the present invention.

FIG. 9 is an example of a processing method according to Embodiment 2 ofthe present invention.

FIG. 10 is an example of a processing method according to Embodiment 3of the present invention.

FIG. 11 is a second example of a processing method according toEmbodiment 3 of the present invention.

FIG. 12 is a third example of a processing method according toEmbodiment 3 of the present invention.

FIG. 13 is an example of a processing method according to Embodiment 4of the present invention.

FIG. 14 is a second example of a processing method according toEmbodiment 4 of the present invention.

FIG. 15 is a third example of a processing method according toEmbodiment 4 of the present invention.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described below in detailwith reference to the drawings.

LTE (and LTE-A Pro) and NR may be defined as different RATs. NR may bedefined as a technology included in LTE. LTE may be defined as atechnology included in NR. LTE capable of connecting with NR throughMulti RAT Dual connectivity may be distinguished from conventional LTE.The present embodiment may be applied to NR, LTE, and other RATs. Termsrelated to LTE and NR are used in the following description. However,the present invention may be applied to other technologies using otherterms. The term E-UTRA in the present embodiment may be replaced withthe term LTE, or the term LTE may be replaced with the term E-UTRA.

FIG. 1 is a schematic diagram of a communication system according toembodiments of the present invention.

An E-UTRA 100 is a radio access technology described in NPL 3 or thelike, and is constituted by Cell Groups (CG) configured in one ormultiple frequency bands. An E-UTRAN Node B (cNB) 102 is a base stationapparatus of E-UTRA. An Evolved Packet Core (EPC) 104 is a core networkdescribed in NPL 14 or the like and is designed as a core network forE-UTRA. An interface 112 is an interface between the eNB 102 and the EPC104, where there is a Control Plane (CP) through which control signalstransfer and a User Plane (UP) through which user data transfers.

An NR 106 is a new radio access technology that is currently beingstudied by the 3GPP and includes Cell Groups (CGs) that are configuredin one or multiple frequency bands. A gNode B (gNB) 108 is an NR basestation apparatus. A 5GC 110 is a new core network for NR that iscurrently being studied by 3GPP, and is described in NPL 2 and the like.

An interface 114 is an interface between the eNB 102 and the 5GC 110, aninterface 116 is an interface between the gNB 108 and the 5GC 110, aninterface 118 is an interface between the gNB 108 and the EPC 104, aninterface 120 is an interface between the eNB 102 and the gNB 108, andan interface 124 is an interface between the EPC 104 and 5GC 110. Theinterface 114, the interface 116, the interface 118, the interface 120,and the interface 124 are interfaces that transfer CP only, or UP only,or both the CP and the UP, and details are being discussed by 3GPP. Theinterface 114, the interface 116, the interface 118, the interface 120,and the interface 124 may not exist depending on communication systemsprovided by the network operators.

A UE 122 is a terminal apparatus supporting NR or supporting both theE-UTRA and the NR.

FIG. 2 is a diagram of Protocol Stacks of UP and CP of a terminalapparatus and a base station apparatus in E-UTRA radio access layersaccording to embodiments of the present invention.

FIG. 2(A) is a diagram of a protocol stack of the UP used in a case thatthe UE 122 communicates with the eNB 102.

A Physical layer (PHY) 200 is a radio physical layer for providing atransmission service to a higher layer by using Physical Channels. ThePHY 200 is connected with a Medium Access Control layer (MAC) 202 thatis a higher layer described below via Transport Channels. Data isexchanged between the MAC 202 and the PHY 200 via transport channels.Data is transmitted and/or received via radio physical channels betweenthe PHYs of the UE 122 and the eNB 102.

The MAC 202 maps various Logical Channels to various transport channels.The MAC 202 is connected with a Radio Link Control layer (RLC) 204 thatis a higher layer described below via logical channels. The logicalchannels are roughly classified depending on the types of informationtransmitted, specifically, classified into control channels fortransmitting control information and traffic channels for transmittinguser information. The MAC 202 has a function of controlling the PHY 200in order to perform discontinuous reception and transmission (DRX andDTX), a function of performing a Random Access procedure, a function ofreporting transmit power information, a function of performing HARQcontrol, and the like (NPL 7).

The RLC 204 divides (Segmentation) data received from a Packet DataConvergence Protocol Layer (PDCP) 206 which is a higher layer describedbelow, and adjusts the data size such that a lower layer can properlytransmit data. The RLC 200 also has a function of ensuring Quality ofService (QoS) required for each piece of data. In other words, the RLC204 has a function of data retransmission control or the like (NPL 6).

The PDCP 206 may have a header compression function of compressingunnecessary control information in order to efficiently transmit an IPPacket, which is user data, in a radio segment. The PDCP 206 may alsohave a data encryption function (NPL 5).

Note that data processed in the MAC 202, the RLC 204, and the PDCP 206is referred to as a MAC Protocol Data Unit (PDU), an RLC PDU, and a PDCPPDU, respectively. Data transferred from a higher layer to the MAC 202,the RLC 204, and the PDCP 206, or data transferred to a higher layer isreferred to as a MAC Service Data Unit (SDU), an RLC SDU, and a PDCPSDU, respectively.

FIG. 2(B) is a diagram of a protocol stack of the CP used in a case thatthe UE 122 communicates with the eNB 102.

In addition to the PHY 200, the MAC 202, the RLC 204, and the PDCP 206,there is a Radio Resource Control layer (RRC) 208 in the protocol stackof CP. The RRC 208 configures or reconfigures Radio Bearers (RBs) or thelike to control the logical channels, the transport channels, and thephysical channels. The RBs may be classified into a Signaling RadioBearer (SRB) and a Data Radio Bearer (DRB), and the SRB may be used as apath for transmitting an RRC message which is control information. TheDRB may be used as a path for transmitting user data. Each RB may beconfigured between the RRCs 208 of the eNB 102 and the UE 122 (NPL 4).

The functional classification of the MAC 202, the RLC 204, the PDCP 206,and the RRC 208 described above is an example, and some or all of therespective functions may not be implemented. Some or all of thefunctions of each layer may be included in another layer.

FIG. 3 is a diagram of Protocol Stacks of UP and CP of a terminalapparatus and a base station apparatus in NR radio access layersaccording to embodiments of the present invention.

FIG. 3(A) is a diagram of a protocol stack of the UP used in a case thatthe UE 122 communicates with the gNB 108.

A Physical layer (PHY) 300 is a radio physical layer of NR and mayprovide a transmission service to a higher layer by using PhysicalChannels. The PHY 300 may be connected with a Medium Access Controllayer (MAC) 302 which is a higher layer described below via TransportChannels. Data may be exchanged between the MAC 302 and the PHY 300 viatransport channels. Data may be transmitted and/or received between thePHYs of the UE 122 and the gNB 108 via radio physical channels. Detailsof the PHY 300 are different from those of the radio physical layer PHY200 of E-UTRA and are under discussion by 3GPP.

The MAC 302 may map various Logical Channels to various transportchannels. The MAC 302 may be connected with a Radio Link Control layer(RLC) 304 which is a high layer described below via logical channels.The logical channels are roughly classified depending on the types ofinformation transmitted, and may be classified into control channels fortransmitting control information and traffic channels for transmittinguser information. The MAC 302 may have a function of controlling the PHY300 in order to perform discontinuous reception and transmission (DRXand DTX), a function of performing a Random Access procedure, a functionof reporting transmit power information, a function of performing HARQcontrol, and the like (NPL 13). Details of the MAC 302 are differentfrom those of the MAC 202 of E-UTRA, and are under discussion by 3GPP.

The RLC 304 may divide (Segmentation) data received from a Packet DataConvergence Protocol Layer (PDCP) 206 which is a higher layer describedbelow, and adjust the data size such that a lower layer can properlytransmit data. The RLC 304 may also have a function of ensuring Qualityof Service (QoS) required for each piece of data. In other words, theRLC 304 may have a function of data retransmission control or the like(NPL 12). Details of the RLC 304 are different from those of the RLC 204of E-UTRA, and are under discussion by 3GPP.

The PDCP 306 may have a header compression function of compressingunnecessary control information in order to efficiently transmit an IPPacket, which is user data, in a radio segment. The PDCP 306 may alsohave a data encryption function (NPL 11). Details of the PDCP 306 aredifferent from those of the PDCP 206 of E-UTRA, and are under discussionby 3GPP.

A Service Data Adaptation Protocol (SDAP) 310 may perform mapping of adownlink QoS flow and a DRB transmitted from the core network to theterminal apparatus via the base station apparatus, perform mapping of anuplink QoS information flow and a DRB transmitted from the terminalapparatus to the core network via the base station apparatus, and have afunction of storing mapping rule information (NPL 16). The QoS flowincludes one or multiple Service Data Flows (SDF) that are processed bythe same QoS policy (NPL 2). The SDAP may have a function of ReflectiveQoS, which performs a mapping of an uplink QoS flow and a DRB, based oninformation of a downlink QoS flow (NPL 2, NPL 16). Details are underdiscussion by 3GPP.

Note that the IP layer, and the Transmission Control Protocol (TCP)layer, the User Datagram Protocol (UDP) layer, the application layer,and the like, higher than the IP layer, are higher layers of the SDAP(not illustrated). In the SDAP of the terminal apparatus, a layer forperforming association between a service data flow and a QoS flow isalso a higher layer of the SDAP.

Note that data processed in the MAC 302, the RLC 304, the PDCP 306, andthe SDAP 310 may be referred to as a MAC Protocol Data Unit (PDU), anRLC PDU, a PDCP PDU, and an SDAP PDU, respectively. Data transferredfrom a higher layer to the MAC 202, the RLC 204, and the PDCP 206, ordata transferred to a higher layer may be referred to as a MAC ServiceData Unit (SDU), an RLC SDU, a PDCP SDU, and an SDAP SDU, respectively.

FIG. 3(B) is a diagram of a protocol stack of the CP used in a case thatthe UE 122 communicates with the gNB 108.

In addition to the PHY 300, the MAC 302, the RLC 304, and the PDCP 306,there is a Radio Resource Control layer (RRC) 308 in the protocol stackof CP. The RRC 308 may configure or reconfigure Radio Bearers (RBs) orthe like to control the logical channels, the transport channels, andthe physical channels. The RBs may be classified into a Signaling RadioBearer (SRB) and a Data Radio Bearer (DRB), and the SRB may be used as apath for transmitting an RRC message which is control information. TheDRB may be used as a path for transmitting user data. Each RB may beconfigured in the RRCs 308 of the gNB 108 and the UE 122 (NPL 10).

The functional classification of the MAC 302, the RLC 304, the PDCP 306,the SDAP 310, and the RRC 308 described above is an example, and some orall of the respective functions may not be implemented. Some or all ofthe functions of each layer may be included in another layer.

Note that, according to embodiments of the present invention, the MAC202, the RLC 204, the PDCP 206, and the RRC 208 may be referred to asMAC for E-UTRA or MAC for LTE, RLC for E-UTRA or RLC for LTE, PDCP forE-UTRA or PDCP for LTE, and RRC for E-UTRA or RRC for LTE, respectively,to distinguish protocols of E-UTRA and protocols of NR hereinbelow. TheMAC 302, the RLC 304, the PDCP 306, and the RRC 308 may also be referredto as MAC for NR, RLC for NR, RLC for NR, and RRC for NR, respectively.Alternatively, the PDCP 306 may be described by using space such asE-UTRA PDCP or LTE PDCP, and NR PDCP.

As illustrated in FIG. 1, the eNB 102, the gNB 108, the EPC 104, and the5GC 110 may be connected to one another via the interface 112, theinterface 116, the interface 118, the interface 120, and the interface114. Thus, the RRC 208 in FIG. 2 may be replaced with the RRC 308 inFIG. 3 to support various communication systems. The PDCP 206 in FIG. 2may also be replaced with the PDCP 306 in FIG. 3. The RRC 308 in FIG. 3may include the functions of the RRC 208 in FIG. 2. The PDCP 306 in FIG.3 may be the PDCP 206 in FIG. 2.

Embodiment 1

Embodiment 1 of the present invention will be described with referenceto FIG. 1, FIG. 2, and FIG. 4 to FIG. 8.

FIG. 4 is a diagram illustrating an example of a flow of an RRCconnection reconfiguration procedure according to each embodiment of thepresent invention.

The RRC Connection Reconfiguration procedure includes procedures usedfor handover, Measurement, and the like, in addition to establishing,changing, and releasing of the RB, and changing, releasing, and the likeof the secondary cell in LTE as disclosed in NPL 4. In MR-DC,especially, in E-UTRA-NR Dual Connectivity (EN-DC), which is MR-DC in acase that the core network is the EPC 104 and the master node is the eNB102, and NG-RAN E-UTRA-NR Dual Connectivity (NGEN-DC), which is MR-DC ina case that the core network is the 5GC 110 and the master node is theeNB 102, the RRC connection reconfiguration procedure is used not onlyfor LTE, but also to perform a part of handover, Measurement, and thelike, in addition to performing a part of establishment, change, andrelease of the RB, and change, release, and the like of the secondarycell in NR as disclosed in NPL 10. In each embodiment of the presentinvention, the procedures used for establishing, changing, and releasingthe RB, adding, changing, and releasing a cell group, the handover andMeasurement, and the like in NR may be referred to as an RRC connectionreconfiguration procedure, or may have another designation. Theprocedures used for establishing, changing, and releasing the RB,adding, changing, and releasing a cell group, the handover andMeasurement, and the like in each embodiment of the present inventionmay be procedures in NR as disclosed in NPL 10, and may be referred toas an RRC connection reconfiguration procedure. In each embodiment ofthe present invention, an RRC connection reconfiguration message(RRCConnectionReconfigration) transmitted from the eNB 102 to the UE 122may be replaced with an RRC reconfiguration message RRCReconfigrationtransmitted from the gNB 108 to the UE 122.

In the RRC connection reconfiguration procedure, the UE 122 receives anRRC connection reconfiguration message (RRCConnectionReconfigration)from the eNB 102 (step S400), and performs various configurations suchas processing of configuration of DRBs or the like, for example, inaccordance with the information included in the RRC connectionreconfiguration message (step S402). After step S402, the UE 122 maytransmit an RRC connection reconfiguration complete message(RRCConnectionReconfigrationComplete), or the like to the eNB 102 (notillustrated).

FIG. 5 is a block diagram illustrating a configuration of a terminalapparatus (UE 122) according to each embodiment of the presentinvention. Note that FIG. 5 illustrates only main components closelyrelated to an aspect of the present invention in order to avoidcomplicated explanation.

The UE 122 illustrated in FIG. 5 includes a receiver 500 configured toreceive an RRC connection reconfiguration message from the eNB 102, anda processing unit 502 configured to process the message.

FIG. 6 is an example of information related to LTE and Abstract SyntaxNotation One (ASN.1) description of the information, of the DRBconfiguration in the cell group of the master node in EN-DC and NGEN-DC,of the information included in the RRC connection reconfigurationmessage in FIG. 4, in each embodiment of the present invention. Thespecifications related to RRC (NPL 4 and NPL 10) in the 3GPP describemessages, information (Information Element (IE)), and the like relatedto RRC by using ASN.1. In the example of ASN.1 of FIG. 6, <omitted> and<partly omitted> are not part of the description of ASN.1, but indicatethat other pieces of information are omitted. Note that there may alsobe omitted information in a part where neither <omitted> nor <partlyomitted> is indicated. Note that ASN.1 in FIG. 6 does not exactly followthe ASN.1 notation method, but is an example of parameters of DRBconfiguration in an aspect of the present invention, and other names orother notations may be used. The example of ASN.1 in FIG. 6 illustratesonly an example about main information closely related to an aspect ofthe present invention in order to avoid complicated explanation.

The information represented by fullConfig in FIG. 6 is information forindicating that a full configuration is applied, and may indicate that afull configuration is applied by using true, enable, or the like. Theinformation represented by DRB-ToAddModList may be a list of informationfor indicating a configuration of DRBs to be added or modifiedrepresented by DRBToAddMod. The information represented byeps-Beareridentity in DRB-ToAddMod (information for indicating aconfiguration of DRBs to be added or modified) may be information of EPSbearer identities for identifying EPS bearers described in NPL 3. In theexample of FIG. 6, an integer value from 0 to 15 is used, but anothervalue may be used. Information of an EPS bearer identity may correspondto the DRB to be configured in a one-to-one manner. The informationrepresented by DRB-Identity in the information for indicating theconfiguration of the DRBs to be added or modified is information of theDRB identities of the DRBs to be added or modified. In the example ofFIG. 6, an integer value from 1 to 32 is used, but another value may beused. The information represented by pdcp-Config in the information forindicating the configuration of the DRBs to be added or modified may beinformation related to a configuration of an LTE PDCP entity in order toestablish or change the PDCP 206.

Some or all of the pieces of the information illustrated in FIG. 6 maybe optional. In other words, the information illustrated in FIG. 6 maybe included in the RRC connection reconfiguration message as necessary.For example, the information related to the configuration of the LTEPDCP entity may be included in a case that the LTE PDCP is used as thePDCP of the DRB in the UE 122 corresponding to EN-DC, or the informationrelated to the configuration of the LTE PDCP entity may not be includedin a case that the NR PDCP is used.

Note that in the UE 122, the configuration of the PDCP entity isconfigured depending on the corresponding RRC entity. In other words,the LTE PDCP entity configuration is configured depending on the RRCentity for LTE described in NPL 4, and the configuration of the NR PDCPentity is configured depending on the RRC entity for NR described in NPL10. In a process performed in the RRC entity for LTE, it is determinedwhether the LTE PDCP is established or configured, and in a processperformed in the RRC entity for NR, it is determined whether the NR PDCPis established or configured. Note that, in a case that informationrelated to configuration of NR such as information related to theconfiguration of the NR PDCP entity is included in the RRC connectionreconfiguration message received from the eNB 102 in the form of acontainer or the like, the UE 122 decodes and configures the NR RRCentity.

Note that in each embodiment of the present invention, information forindicating a configuration of a DRB to be added or modified may bedescribed as a DRB configuration, information of an EPS bearer identitymay be described as an EPS bearer identity, information of a DRBidentity may be described as a DRB identity, and information related toa configuration of an LTE PDCP entity may be described as an LTE PDCPconfiguration.

FIG. 7 illustrates an example of a processing method of the processingunit 502 of the UE 122 in FIG. 5 according to Embodiment 1 of thepresent invention, and FIG. 8 illustrates another example of aprocessing method of the processing unit 502 of the UE 122 in FIG. 5according to Embodiment 1 of the present invention. Note that in thefollowing description, a DRB configuration is included in a list of DRBconfigurations, and the processing for a DRB configuration in theprocessing unit 502 of the UE 122 is performed for each of DRBconfigurations included in a list of DRB configurations.

An example of a DRB configuration procedure will be described withreference to FIG. 5 to FIG. 7.

The processing unit 502 of the UE 122 confirms that the RRC connectionreconfiguration message including the DRB configuration received by thereceiver 500 includes information for indicating that a fullconfiguration is applied (step S700).

Next, in a case that the value of a DRB identity included in the DRBconfiguration is not part of the current configuration of the UE 122,and that an established DRB having the DRB identity is established withan LTE PDCP entity, the processing unit 502 of the UE 122 associates theestablished DRB with the EPS bearer identity (step S702). In a case thatthe value of a DRB identity included in the DRB configuration is notpart of the current configuration of the UE 122, and that an establishedDRB having the DRB identity is not established with an LTE PDCP entity,the processing unit 502 of the UE 122 does not associate the establishedDRB with the EPS bearer identity. Note that “in a case that anestablished DRB having the DRB identity is established with an LTE PDCPentity” may be replaced with “in a case that an established DRB havingthe DRB identity is established with a PDCP entity by LTE,” or may bereplaced with “an LTE PDCP entity configuration is included in the DRBconfiguration.” Note that “in a case that an LTE PDCP entity isestablished” refers to a case that establishment of a PDCP entity isestablished in an RRC entity for LTE, and “an LTE PDCP configuration isincluded in the DRB configuration” refers to that a PDCP configurationis included in the DRB configuration of an RRC entity for LTE. Note that“in a case that an established DRB having the DRB identity is notestablished with an LTE PDCP entity” may be replaced with “in a casethat an established DRB having the DRB identity is not established witha PDCP entity by LTE,” or may be replaced with “an LTE PDCP entityconfiguration is not included in the DRB configuration.” Note that “in acase that an LTE PDCP entity is not established” refers to a case thatestablishment of a PDCP entity is not established in an RRC entity forLTE, and “an LTE PDCP configuration is not included in the DRBconfiguration” refers to that a PDCP configuration is not included inthe DRB configuration of an RRC entity for LTE.

Note that in FIG. 7, the order in which each piece of the information isconfirmed may not be this order. Confirmation that information forindicating that a full configuration is applied is included may beperformed after confirming in step S702 that the value of theinformation of the DRB identity is not part of the current configurationof the UE 122 or after confirming that an LTE PDCP entity isestablished.

Next, another example of a DRB configuration procedure will be describedwith reference to FIG. 5, FIG. 6, and FIG. 8.

The processing unit 502 of the UE 122 confirms that the RRC connectionreconfiguration message including the DRB configuration received by thereceiver 500 does not include information for indicating that a fullconfiguration is applied (step S800).

Next, in a case that the value of a DRB identity included in the DRBconfiguration is not part of the current configuration of the UE 122,and in a case that an established DRB having the DRB identity isestablished with an LTE PDCP entity, the processing unit 502 of the UE122 notifies a higher layer of the information that the DRB has beenestablished and the EPS bearer identity of the established DRB (stepS802). In a case that the value of a DRB identity included in the DRBconfiguration is not part of the current configuration of the UE 122,and in a case that an established DRB having the DRB identity is notestablished with an LTE PDCP entity, the processing unit 502 of the UE122 does not notify a higher layer of the information that the DRB hasbeen established and the EPS bearer identity of the established DRB.Note that “in a case that an established DRB having the DRB identity isestablished with an LTE PDCP entity” may be replaced with “in a casethat an established DRB having the DRB identity is established with aPDCP entity by LTE,” or may be replaced with “an LTE PDCP entityconfiguration is included in the DRB configuration.” Note that “in acase that an LTE PDCP entity is established” refers to a case thatestablishment of a PDCP entity is established in an RRC entity for LTE,and “an LTE PDCP configuration is included in the DRB configuration”refers to that a PDCP configuration is included in the DRB configurationof an RRC entity for LTE. Note that “in a case that an established DRBhaving the DRB identity is not established with an LTE PDCP entity” maybe replaced with “in a case that an established DRB having the DRBidentity is not established with a PDCP entity by LTE,” or may bereplaced with “an LTE PDCP entity configuration is not included in theDRB configuration.” Note that “in a case that an LTE PDCP entity is notestablished” refers to a case that establishment of a PDCP entity is notestablished in an RRC entity for LTE, and “an LTE PDCP configuration isnot included in the DRB configuration” refers to that a PDCPconfiguration is not included in the DRB configuration of an RRC entityfor LTE.

Note that in FIG. 8, the order in which each piece of the information isconfirmed may not be this order. Confirmation that information forindicating that a full configuration is applied is not included may beperformed after confirming in step S802 that the value of theinformation of the DRB identity is not part of the current configurationof the UE 122 or after confirming that an LTE PDCP entity isestablished.

In this way, according to Embodiment 1 of the present invention, theterminal apparatus can lower complexity of protocol processing andcommunicate efficiently.

Embodiment 2

Embodiment 2 of the present invention will be described with referenceto FIG. 4 to FIG. 6, and FIG. 9. Note that Embodiment 2 of the presentinvention may be adapted in a case that EN-DC is configured.

FIG. 9 illustrates an example of a processing method of the processingunit 502 of the UE 122 in FIG. 5 according to Embodiment 2 of thepresent invention. Note that in the following description, a DRBconfiguration is included in a list of DRB configurations, and theprocessing for a DRB configuration in the processing unit 502 of the UE122 is performed for each of DRB configurations included in a list ofDRB configurations.

The processing unit 502 of the UE 122 confirms that the RRC connectionreconfiguration message including the DRB configuration received fromthe receiver 500 includes information for indicating that a fullconfiguration is applied, the value of the EPS bearer identity includedin the DRB configuration is part of the current configuration of the UE122, and the PDCP entity is configured for the DRB corresponding to theEPS bearer identity. (step S900).

Next, the processing unit 502 of the UE 122 releases the PDCP entity.(step S902).

In this way, according to Embodiment 2 of the present invention, theterminal apparatus can lower complexity of protocol processing andcommunicate efficiently.

Embodiment 3

Embodiment 3 of the present invention will be described with referenceto FIG. 4 to FIG. 6, and FIG. 10 to FIG. 12. In Embodiment 3, therelease process of the DRB with PDCP version change from the LTE PDCP tothe NR PDCP or from the NR PDCP to the LTE PDCP is described. Note thatEmbodiment 3 of the present invention may be adapted in a case thatEN-DC is configured.

FIG. 11 illustrates an example of a processing method of the processingunit 502 of the UE 122 in FIG. 5 according to Embodiment 3 of thepresent invention, FIG. 10 illustrates a second example of a processingmethod of the processing unit 502 of the UE 122 in FIG. 5 according toEmbodiment 3 of the present invention, and FIG. 12 illustrates a thirdexample of a processing method of the processing unit 502 of the UE 122in FIG. 5 according to Embodiment 3 of the present invention. Note thatin the following description, a DRB configuration is included in a listof DRB configurations, and the processing for a DRB configuration in theprocessing unit 502 of the UE 122 is performed for each of DRBconfigurations included in a list of DRB configurations.

In FIG. 10, the processing unit 502 of the UE 122 confirms that the RRCconnection reconfiguration message received from the receiver 500includes a DRB identity of a DRB to be released, and that a new DRB isadded to an EPS bearer identity corresponding to the DRB identity. (stepS1000).

Next, the processing unit 502 of the UE 122 releases the DRB identity.(step S1002). In step S1002, the processing unit 502 of the UE 122 mayfurther transmit a notification to an NR RRC entity that a new DRB isestablished for the EPS bearer identity corresponding to the DRBidentity.

In FIG. 11, the processing unit 502 of the UE 122 confirms that the RRCconnection reconfiguration message received from the receiver 500includes a DRB identity of a DRB to be released. (step S1100).

Next, the processing unit 502 of the UE 122 checks that a PDCP entity isconfigured for the DRB to be released and that the RRC connectionreconfiguration message does not include information of a PDCP versionchange (not illustrated in FIG. 6) (step S1102). In a case of confirmed,the processing unit 502 of the UE 122 notifies a higher layer of the EPSbearer identity corresponding to the DRB identity and the releaseinformation of the DRB. (step S1104)

In step S1102, in a case that the processing unit 502 of the UE 122fails to confirm that an PDCP entity is configured for the DRB to bereleased and that the RRC connection reconfiguration message does notinclude information of a PDCP version change, the processing unit 502 ofthe UE 122 checks that the RRC connection reconfiguration messageincludes information of a PDCP version change, and in a case ofconfirmed, releases the DRB identity (step S1106).

In FIG. 12, the processing unit 502 of the UE 122 confirms that the RRCconnection reconfiguration message received from the receiver 500includes a DRB identity of a DRB to be released. (step S1200).

Next, the processing unit 502 of the UE 122 checks that an indication tonotify the release is set for the DRB to be released (not illustrated inFIG. 6) (step S1202). In a case of confirmed, the processing unit 502 ofthe UE 122 notifies a higher layer of the EPS bearer identitycorresponding to the DRB identity and the release information of theDRB. (step S1204)

In step S1202, in a case that the processing unit 502 of the UE 122confirms that an indication to notify the release is not set for the DRBto be released, the processing unit 502 of the UE 122 checks that arelease indication (not illustrated in FIG. 6) of a DRB identity is setfor the DRB identity. In a case of confirmed, the processing unit 502 ofthe UE 122 releases the DRB identity (step S1206).

In this way, according to Embodiment 3 of the present invention, theterminal apparatus can lower complexity of protocol processing andcommunicate efficiently.

Embodiment 4

Embodiment 4 of the present invention will be described with referenceto FIG. 4 to FIG. 6, and FIG. 13 to FIG. 15. In Embodiment 4, the DRBaddition process after releasing the DRB with PDCP version change fromthe LTE PDCP to the NR PDCP or from the NR PDCP to the LTE PDCP isdescribed. Note that Embodiment 4 of the present invention may beadapted in a case that EN-DC is configured.

FIG. 13 illustrates an example of a processing method of the processingunit 502 of the UE 122 in FIG. 5 according to Embodiment 4 of thepresent invention, FIG. 14 illustrates a second example of a processingmethod of the processing unit 502 of the UE 122 in FIG. 5 according toEmbodiment 4 of the present invention, and FIG. 15 illustrates a thirdexample of a processing method of the processing unit 502 of the UE 122in FIG. 5 according to Embodiment 4 of the present invention. Note thatin the following description, a DRB configuration is included in a listof DRB configurations, and the processing for a DRB configuration in theprocessing unit 502 of the UE 122 is performed for each of DRBconfigurations included in a list of DRB configurations.

In FIG. 13, the processing unit 502 of the UE 122 confirms that the RRCconnection reconfiguration message received from the receiver 500includes a DRB configuration, and that the DRB configuration includes aDRB identity and an EPS bearer identity, and confirms that the DRBidentity is not part of the current configuration of UE 122, and that aDRB was configured for the EPS bearer identity before receiving the RRCconnection reconfiguration message (step S1300).

Next, the processing unit 502 of the UE 122 associates the DRBestablished according to the DRB configuration with the EPS bearer (stepS1302).

In FIG. 14, the processing unit 502 of the UE 122 confirms that the RRCconnection reconfiguration message received from the receiver 500includes a DRB configuration, and that the DRB configuration includes aDRB identity and an EPS bearer identity, and confirms that the DRBidentity is not part of the current configuration of UE 122, and thatthe RRC connection reconfiguration message includes information of aPDCP version change (step S1400). In a case of confirmed, the processingunit 502 of the UE 122 associates the DRB established according to theDRB configuration with the EPS bearer (step S1402).

In FIG. 15, the processing unit 502 of the UE 122 confirms that the RRCconnection reconfiguration message received from the receiver 500includes a DRB configuration, and that the DRB configuration includes aDRB identity and an EPS bearer identity, and confirms that the DRBidentity is not part of the current configuration of UE 122, and that anindication of association is set for the DRB configuration (step S1500).In a case of confirmed, the processing unit 502 of the UE 122 associatesthe DRB established according to the DRB configuration with the EPSbearer (step S1502). In this way, according to Embodiment 4 of thepresent invention, the terminal apparatus can lower complexity ofprotocol processing and communicate efficiently.

Note that the DRB configuration according to the embodiments of thepresent invention may be included in an RRC Establishment procedure andan RRC Re-Establishment procedure, in addition to the RRC connectionreconfiguration procedure.

In the embodiments of the present invention, “LTE PDCP” is described,but “PDCP” may be described without adding LTE in a case that it isclear to be a PDCP configured by an RRC entity for LTE described in NPL4.

A program running on an apparatus according to an aspect of the presentinvention may serve as a program that controls a Central Processing Unit(CPU) and the like to cause a computer to operate in such a manner as torealize the functions of the above-described embodiments according tothe aspect of the present invention. Programs or the information handledby the programs are temporarily read into a volatile memory, such as aRandom Access Memory (RAM) while being processed, or stored in anon-volatile memory, such as a flash memory, or a Hard Disk Drive (HDD),and then read by the CPU to be modified or rewritten, as necessary.

Note that the apparatuses in the above-described embodiments may bepartially enabled by a computer. In such a case, a program for realizingsuch control functions may be recorded on a computer-readable recordingmedium to cause a computer system to read the program recorded on therecording medium to perform the program. It is assumed that the“computer system” mentioned here refers to a computer system built intothe apparatuses, and the computer system includes an operating systemand hardware components such as a peripheral device. The“computer-readable recording medium” may be any of a semiconductorrecording medium, an optical recording medium, a magnetic recordingmedium, and the like.

Moreover, the “computer-readable recording medium” may include a mediumthat dynamically retains a program for a short period of time, such as acommunication line that is used to transmit the program over a networksuch as the Internet or over a communication line such as a telephoneline, and may also include a medium that retains a program for a fixedperiod of time, such as a volatile memory within the computer system forfunctioning as a server or a client in such a case. The above-describedprogram may be configured to realize some of the functions describedabove, and additionally may be configured to realize the functionsdescribed above, in combination with a program already recorded in thecomputer system.

Each functional block or various characteristics of the apparatuses usedin the above-described embodiments may be implemented or performed on anelectric circuit, that is, typically an integrated circuit or multipleintegrated circuits. An electric circuit designed to perform thefunctions described in the present specification may include ageneral-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA), or other programmable logic devices, discrete gatesor transistor logics, discrete hardware components, or combinationsthereof. The general-purpose processor may be a microprocessor, or theprocessor may be a processor of known type, a controller, amicro-controller, or a state machine instead. The general-purposeprocessor or the above-mentioned circuits may be configured of a digitalcircuit, or may be configured of an analog circuit. In a case that withadvances in semiconductor technology, a circuit integration technologyappears that replaces the present integrated circuits, it is alsopossible to use an integrated circuit based on the technology.

Note that the invention of the present patent application is not limitedto the above-described embodiments. In the embodiment, apparatuses havebeen described as an example, but the invention of the presentapplication is not limited to these apparatuses, and is applicable to aterminal apparatus or a communication apparatus of a fixed-type or astationary-type electronic apparatus installed indoors or outdoors, forexample, an AV apparatus, a kitchen apparatus, a cleaning or washingmachine, an air-conditioning apparatus, office equipment, a vendingmachine, and other household apparatuses.

The embodiments of the present invention have been described in detailabove referring to the drawings, but the specific configuration is notlimited to the embodiments and includes, for example, an amendment to adesign that falls within the scope that does not depart from the gist ofthe present invention. Various modifications are possible within thescope of an aspect of the present invention defined by claims, andembodiments that are made by suitably combining technical meansdisclosed according to different embodiments are also included in thetechnical scope of the present invention. A configuration in whichconstituent elements, described in the embodiments and having mutuallythe same effects, are substituted for one another is also included inthe technical scope of the present invention.

INDUSTRIAL APPLICABILITY

An aspect of the present invention can be utilized, for example, in acommunication system, communication equipment (for example, a cellularphone apparatus, a base station apparatus, a wireless LAN apparatus, ora sensor device), an integrated circuit (for example, a communicationchip), or a program.

REFERENCE SIGNS LIST

-   100 E-UTRA-   102 cNB-   104 EPC-   106 NR-   108 gNB-   110 5GC-   112, 114, 116, 118, 120, 124 Interface-   122 UE-   200, 300 PHY-   202, 302 MAC-   204, 304 RLC-   206, 306 PDCP-   208, 308 RRC-   310 SDAP-   500 Receiver-   502 Processing unit

1.-4. (canceled)
 5. A terminal apparatus for communicating with one ormore base station apparatuses, the terminal apparatus comprising: areceiver configured to receive an RRC connection reconfiguration messageincluding a DRB configuration from the one or more base stationapparatuses, the DRB configuration including a DRB identity and an EPSbearer identity; and processing circuitry configured to associate anestablished DRB with the EPS identity in a case that the DRB identity isnot part of a current configuration of the terminal apparatus, and theDRB was configured with the EPS bearer identity, and the DRB isestablished due to PDCP version change from NR PDCP to E-UTRA PDCP.
 6. Acommunication method for a terminal apparatus for communicating with oneor more base station apparatuses, the communication method comprisingthe steps of: receiving an RRC connection reconfiguration messageincluding a DRB configuration from the one or more base stationapparatuses, the DRB configuration including a DRB identity and an EPSbearer identity; and associating an established DRB with the EPSidentity in a case that the DRB identity is not part of a currentconfiguration of the terminal apparatus, the DRB was configured for theEPS bearer identity, and the DRB is established due to PDCP versionchange from NR PDCP to E-UTRA PDCP.
 7. A base station apparatus forcommunicating with a terminal apparatus, the base station apparatuscomprising: a transmitter configured to transmit an RRC connectionreconfiguration message including a DRB configuration to the terminalapparatus, the DRB configuration including a DRB identity and an EPSbearer identity; and processing circuitry configured to cause theterminal apparatus to perform processing to associate an established DRBwith the EPS identity in a case that the DRB identity is not part of acurrent configuration of the terminal apparatus, and the DRB wasconfigured for the EPS bearer identity, and the DRB is established dueto PDCP version change from NR PDPC to E-UTRA PDCP.
 8. A communicationmethod for a base station apparatus for communicating with a terminalapparatus, the communication method comprising the steps of:transmitting an RRC connection reconfiguration message including a DRBconfiguration to the terminal apparatus, the DRB configuration includinga DRB identity and an EPS bearer identity; and causing the terminalapparatus to perform processing to associate an established DRB with theEPS identity in a case that the DRB identity is not part of a currentconfiguration of the terminal apparatus, the DRB was configured for theEPS bearer identity, and the DRB is established due to PDCP versionchange from NR PDCP to E-UTRA PDCP.